Knitting machine



Feb. 20, 1934, s. A. WELCH ETAL 58 KNITTING MAHINE Filed April 10. 1931A. WELCH F- GUYLER T ASHBY M H. BOALER INVENTO H5 M 40 mronusvs PatentedFeb. 20, 1934 UNITED STATES PATENT OFFICE 1,947,958 KNITTING MACHINEApplication April 10,1931, Serial No. 529,034.

and in Great Britain June 16, 1930 7 Claims. (Cl. 66-146) This inventionrelates to the manufacture of.

knitted fabrics and particularly to the manufacture of warp knittedfabrics, thatis, fabrics in which a number of warp threads are knittedtogether in each course.

In the usual method of producing such fabrics a number of warp threadsare drawn from a creel, beam ora number of sectional beams by a feedingdevice, passed over a tension bar, and thence 'to thread guides whichguide the threads to the needles, where they are knitted into fabric.Variations in the tension of the thread take place during knitting, andthese variations cause the tension bar to move against the action ofsprings or weights by which it is loaded. The feeding device is driventhroughafriction clutch, operated by the movements of the tension bar,and in this manner is caused to feedthe threads at a rate varying withthe tension in the threads. The fabric is passed round a porcupineroller, i. e. a roller having a roughened surface, consisting of coarseemery cloth or the like, which grips the fabric across its whole width.The porcupine roller is generally driven at a constant speed, whichdetermines the linear rate at which the fabric is produced, and theapproximate tension under which it is knitted, but it may be drivenunder a constant torque, so that the fabric is removed from the needlesunder constant tension. After passing round the porcupine roller, thefabric is wound on to a take-up roller, generally driven by frictionwheels.

According to this invention the warp threads are taken from a suitablesource of supply by a feeding device, whichforwards them at a constantrate 'to thread guides which lead them to the needles, a tension barbeing interpose between. the feeding device and the needles to equalizethe tension during knitting. In this manner a fabric is produced whichis uniform as regards the size of the loops and their shape, since thequantity of thread fed to each loop is uniform. e

The warp threads maybe taken from any suitable source of supply, such asa creel or a beam, or a number of sectional beams, and the threads maybe divided into any desired number of sets,-

nipping rollers, of any desired materials, between non-yielding roller.

and the slack will accumulate between the beam and the feeding device.Ultimately this accumulated slack may curl on itself and be drawnthrough the device in a knot, producing a blemish on the fabric. Forthis reason it is preferred to use a feeding device which will allow theslacker threads to pass through uniformly as they are wound off thebeams, so that no slack accumulates. The slackness, which of course isonly very slight, will then be distributed along the length of thefabric, where its effect will be negligible.

A convenient form of feeding device for this purpose comprises a pair ofconstantly.driven 70 which the warpthreads are passed. In this case theeffect may be produced by making on the surface of one or both of therollers a pattern of grooves or recesses. This causes the pressure atcertain points, where 'the recesses cross the line of nip of therollers, to be relieved, so that if the thread passing through at suchpoints is slack behind the rollers, the slackness will be drawn through.At the same time nearly all the .threads at any momentare nipped by therollers so that they donot slip through uncontrolledly at once. Thepoints of reduced pressure move along the line of nip so thatthe'threads are successively provided for in this manner. For exampleither of the rollers may be formed with two sets of helical groovesrunning in opposite directions to divide the surface of the roller intoa series of lozenges, or both rollers may have a single series ofhelical grooves, running in the same direction on the two rollers sothat they cross each other at an angle in the nip of the rollers toproduce the equivalent of alozenge pattern on a single roller. One ofthe rollers may conveniently be covered with cork, rubber or otherelastic material, while the other has a steel or other non-yieldingsurface. In such case, the grooves are preferably formed in the I Withsuch rollers the pressure between the steel and the rubber coveredrollers may be varied to give a fine adjustmen of the rate of feed ofthe threads. 1

The take-up of the fabric is preferably arranged to draw the fabric fromthe needles under It is convenient that means should be provided in thedrive of the feeding device for changing the rate of feed of thethreads, so that long and narrow, or rather short and loosely a knittingmachine provided with feeding means' knit. When the fabric is taken upat a constant rate, this rate must be adjusted to correspond to the rateof feeding of the threads, in order that no excess or deficiency of thethread fed to the needles may occur.

The invention will now be described in greater detail with reference tothe accompanying drawing, but it is to be understood that thisdescription is given by way of example only and is in, no respectlimitative.

Figure 1 is a diagrammatic side elevation of and take-up deviceaccording to the invention;

Figure 2 shows a simplified form of fabric take-up device;

Figure 3 shows an elevation of a pair of feed rollers which may be usedin carrying out the invention;

Figure 4 is a detailed front view showing several forms'of feed roller;and

Figure 5 shows spring loading means for a tension bar.

Referring to eFigure 1,,warp threads 5, 5' are taken from warp beams 6,6' through feeding devices which consist of nipping rollers '7, '7' and8, 8'. One of each pair of these rollers, for example '7, '7' is coveredwith cork, rubber, or other elastic material while the other is ofsteel. Means may be provided for adjusting the pressure between therollers '7 and 8 in order to give a fine adjustment of the rate of feedof the threads by varying the compression of the elastic rollers by thesteel rollers.

The two rollers '7, '7' are connected together by means of a chain 10and wheels 9, 9' and the lower of the rollers, '7' is driven from thedrive 11 of the machine by means of a chain 12 and gears 13, the gears13 being exchangeable for other gears of different sizes in order thatthe rate of drive of the feeding device may be altered at will, anddiflerent types of fabric produced as desired.

The warp threads 5 are forwarded by the rollers '7, 8 to tension bars 14mounted on spring loaded arms 15. From the bars 14 the threads 5 pass toguides '16 of the knitting machine and are knitted into a fabric 17 bythe action of needles 18 and pressers 18'. The fabric 1'7 passes to atake-up device which is adapted to collect the fabric under constanttension. This comprises a take-up roller 19 having a slipping frictiondrive roller 19. Before reaching the roller 19 the fabric passes round aporcupine roller 20, the surface of which is covered with emery cloth orthe like which causes the roller 20 to grip the fabric across its wholewidth. The roller 20 is driven.

with a constant torque by means of an endless chain 21 passing round a.sprocket 22 on the shaft 23 of the roller 20. The chain 21 passes rounda further sprocket 24 fitted with a ratchet 25 and loaded with weights29 which impart a constant torque to the porcupine roller 20. When theweight 29 has dropped on account of the rotation of the porcupine roller20 as it feeds the Figure 2 shows a'simplified form of take-up de vicein which a constant torque is applied to the porcupine roller 120 bymeans of a chain or rope 121 passing round a sprocket or pulley 122, thechain terminating in a weight 129. The sprocket 122 is connected to theroller 120 through a ratchet 30 and a pawl, 31. Thus the roller 120 isurged in a counter clockwise direction under the constant torqueimparted by the weight 129. The ratchet 30 and sprocket 122 are, ofcourse, able to rotate in a clockwise direction independent of theroller 120 so as to permit the weight to be wound up at intervals bymeans of the squared end of the shaft 32 to which the member 122 issecured. The take-up device of Fig 2 is intended to replace the take-upmechanism represented by the reference characters 20 to 29 of Fig. 1,the porcupine roller 120 occupying exactly the position of the porcupineroller 20 in Fig. 1.-

Referring to Figures 3 and 4, one of the rollers '7 and 8 is shownprovided on its surface with a recessed pattern, forming grooves orhollows 34 which permit slack threads to pass through the rings of therollers under the pull of the knitting mechanism, so avoidingaccumulation of the slack in front of the rollers. As shown in Figure 3the top roller 8 is carried on the shaft 48 which passes at each endthrough a block 49. Adjustment of the pressurebetween the rollers '7 and8 may be made by means of a screw 50 bearing upon the upper side of theblock 49 and passing through a rigid portion 51 of the machine frame.

In Figure 4 are shown three methods of providing these grooves orrecesses in the feed rollers.

On the left hand side of the figure the upper roller 8 is plain whilethelower roller '7 is provided with helical grooves 35 and 36, thegrooves 35 being right hand and the grooves 36 left hand. These combineto produce a pattern of lozenges 3'7 on the surface of the roller '7. 0nthe right hand side of Figure 4 the roller '7 is plainv while the roller8 is provided with the lozenge pattern. In the middle portion of Figure4, both rollers '7 and 8 each have helical g'rooves38, the grooves inboth rollers being right handed. Between the grooves lands 39 are left,the lands of the two rollers-cooperating to produce an effect upon thethreads which' is surrounded by a compression spring 44.

This spring acts between the extension 42 and lock nuts 45 on the rod 43and so resists downward movement of the bar 14 under the tension of thewarp. The lower end of the rod 43- is pivoted at 46 to a suitable partof the machine frame (not shown). It will be understood that the othertension bar 14' is similarly provided.

What we claim and desire to secure by Letters Patent is:

1. A warp knitting machine comprising a pair of nipping rollers adaptedto vbe driven at a "constant speed so as to feed the warp threads at asubstantially constant rate to the needles of the machine, wherein oneof said rollers is provided with a number of helical grooves running inopposite directions along its surface and forming a lozenge patternthereon so as to provide an interrupted line of contact between therollers which permits any slack threads to be pulled therethrough by thetension imparted to the threads during knitting, and means interposedbetween the feed rollers and the needles to maintain the tension in eachthread substantially constant during knitting;

2; A warp knitting machine comprising a pair of nipping rollers adaptedto forward the warp threads at a substantially constant rate to theneedles of the machine wherein both said rollers are provided with anumber of helical grooves adapted to cross each other at the nip of therollers so as to provide an interrupted line of contact between therollers which permits any slack threads to be pulled therethrough by thetension imparted to the threads during knitting, and means interposedbetween the feeding means and the needles to maintain the tension ineach thread substantially constant during knitting.

' 3. A warp knitting machine comprising means for feeding warp threadsat a substantially constant rate to the needles of the machine, saidmeans being such as vto permit any slack threads to be pulledtherethrough by the tension imparted to the threads during knitting,means interposed between the feeding means and the needles to maintainthe tension in each thread substantially constant during knitting, and atake-up device adapted to draw the fabric from the needles underconstant tension, said take-up device comprising a porcupine roller fordrawing the fabric from the needles, an endless chain passing over asprocket on the porcupine roller and over a second sprocket rotatable inone direction only, said chain being loaded to impart a constant torqueto the porcupine roller, and a take-up roller adapted to collect thefabric delivered from the porcupine roller.

4. A warp knitting machine comprising a pair of nipping rollers adaptedto forward the warp threads at a substantially constant rate to theneedles of the machine wherein at least one of said rollers has itssurface relieved to interrupt theline of contact between the rollers atpoints that move along the line as the rollers rotate,

the interruption thus permitting the slack in any thread to be pulledthrough the nip of the rollers at intervals by the tension imparted tothe threads during knitting, and means interposed between the feedingmeans'and the needles to maintain the tension in each threadsubstantially constant during knitting. 5. A warp knitting machinecomprising a. pair of nipping rollersadapted to forward the warp threadsat a substantially constant rate to the needles of the machine whereinat least one of said rollers has its surface relieved to interrupt theline of contact between the rollers at points that move along the lineas the rollers rotate, the interruption thus permitting the slack in anythread to be pulled through the nip of the rollers at intervals by thetension imparted to the threads during knitting, and a loaded tensionbar interposed between the feeding means and the needles to maintain thetension in each thread substantially constant during knitting. 6. A warpknitting machine comprising a, pair of nipping rollers adapted to bedriven at a constant speed so as to feed the warp threads at asubstantially constant rate to the needles of the machine, one of saidrollers having a yielding surface, means for adjustably pressing therollers together so as to control the feed rate of the threads, at leastone of said rollers having its surface relieved to interrupt the line ofcontact between the rollers at points that move along the lineas therollers rotate, the interruption thus permitting the slack in any threadto be pulled through the nip of the rollers at intervals by the tensionimparted to the threads during knitting, and means interposed betweenthe feeding means and the needles to maintain the tension in each threadsubstantially constant during knitting.

7. A warp knitting machine comprising a pair of nipping rollers adaptedto forward the warp threads at a substantially constant rate to theneedles of the machine wherein at least one of said rollers has itssurface relieved to interrupt the line of contact between the rollers atpoints that move along the line as the rollers rotate, the interruptionthuspermitting the slack in any thread to be pulled through the nip ofthe rollers at intervals by the tension imparted to the threads duringknitting, means interposed between the feeding means and, the needles tomaintain the tension in each thread substantially constant duringknitting, and a take-up device adapted to draw the fabric from theneedles under constant tension.

